ISO SWS/LWS observations of SN 1987A

Abstract

We report on observations of SN 1987A with ISO SWS/LWS made 9 - 11 years after the explosion. No emission from the supernova was seen. In particular, the upper limits on the fluxes of [Fe I] 24.05 microns and [Fe II] 25.99 microns on day 3999 are roughly 1.1 Jy and 1.4 Jy, respectively. Assuming a homogeneous distribution of Ti-44 inside 2000 km/s, we have made theoretical models to estimate the mass of ejected Ti-44. Assessing various uncertainties of the model, we obtain an upper limit of 1.5\EE{-4} solar masses. The implications of this are discussed. The LWS data display continuum emission as well as nebular lines of [O I], [C II] and [O III] from neighboring photoexcited regions in the LMC. The [O III] lines indicate an electron density of 120 +/- 75 cm^{-3}, and the continuum can be explained by dust with a temperature of roughly 37 K. A second dust component with approximately 10 K may also be present.